It has been known to provide one or a plurality of airbags in vehicles to protect occupants in case of vehicle accidents. There have been various types such as a so-called driver airbag that inflates in the vicinity of the center of the steering wheel of an automobile to protect a driver, a curtain airbag that deploys downward inside the window of an automobile to protect an occupant in case of a shock in the lateral direction of the vehicle, a rollover, and a turnover accident, and a side airbag that deploys between an occupant and a side panel to protect the occupant in case of a shock in the lateral direction of a vehicle. The present invention relates to a side airbag device provided in a vehicle seat.
A side airbag device faces the problem of quickly and smoothly deploying an airbag since a space for deploying the airbag is narrow and limited. For example, it is demanded that an airbag quickly deploy and restrain an occupant between a vehicle seat and a door trim.
The present invention has been made in view of the above circumstances and has an object of providing a side airbag device capable of quickly and appropriately restraining an occupant at the initial stage of the deployment of an airbag.
The present invention is applied to a side airbag device including: a bag-shaped airbag that deploys from a lateral portion of a vehicle seat toward a front side of a vehicle; and an inflator that supplies inflation gas into the airbag. The airbag has, at least at a lower portion thereof, a lower tuck-in region tucked into the airbag. Further, at least a part of the lower tuck-in region is folded into a fan shape and forms a radial folded region folded into a pleated shape along a line extending rearward in a radial direction from a central point of the fan shape positioned on a front side of the airbag.
According to the present invention having the above configurations, at least the part of the lower tuck-in region forms the radial folded region folded into the pleated shape along the line extending rearward in the radial direction from the central point positioned on the front side of the airbag. Therefore, the rear portion of the radial folded region having a large folding width first deploys at the initial stage of the deployment of the airbag. Therefore, it becomes possible to quickly restrain the vicinity of the lateral portion of the lumbar of an occupant sitting on a vehicle seat.
In order to easily fold and largely expand the airbag, the central point of the folded region having the fan shape is preferably provided to be positioned on a marginal portion of the airbag on the front side of the vehicle when the airbag deploys. On the other hand, when the central point is virtually set outside the marginal portion of the airbag on the front side of the vehicle, the front portion of the airbag has a large folding width, which brings about an advantage that the front portion also deploys relatively quickly. Further, when the central point is set on the inside of the marginal portion of the airbag on the front side of the vehicle, the fold line can have a large inclination angle, which makes it possible to more quickly deploy the rear lower end of the airbag.
The side airbag device can be so configured that a plurality of parallel folded regions folded along at least two substantially parallel lines is provided above the radial folded region, and that the radial folded region is tucked between the parallel folded regions. At this time, at least a part of the radial folded region is preferably brought into a state of protruding from the lower tuck-in region in a state in which the parallel folded regions are tucked into the airbag. This is because the radial folded region is intended to deploy prior to the parallel folded regions in the present invention.
The fold lines of the parallel folded regions can be inclined such that front sides thereof are lowered with respect to a horizon. Thus, space capacity of the initially-deploying rearward lower portion (radial folded region) of the airbag can be increased.
The side airbag device in accordance with the present invention is preferably so configured that the inflator is accommodated on a rear side of the vehicle inside the airbag, and that an upper fold line of the parallel folded regions is positioned in a vicinity of a lower end of the inflator. Further, a baffle member that vertically distributes the gas discharged from the inflator is preferably arranged inside the airbag, and the lower tuck-in region is preferably arranged below the baffle member.
When the baffle member is inclined such that a front side thereof is lowered with respect to the horizon, the same effect as that produced when the parallel folded regions are inclined such that the front sides thereof are lowered can be expected.